Hard metallic composition



"Patented Sept. 2, 1930 UNITED STATES PATENT OFFICE BOY L. ADAMS, OFSCHENECTADY, NEW YORK, ASSIGNOR 170 GENERAL ELECTRIC COM PANY, ACORPORATION OF NEW YORK HARD METALLIC COMPOSITION no Drawing.Application filed m 31,

My invention relates broadly to hard metallic compositions andparticularly to an improved method of making metallic compositions ofthe type set forth in the patent to Karl Schrdter, 1,549,615, grantedAug. 11, 1925, and in the application of Karl Schroter, Serial No.104,613, filed April 26, 1926, now Patent No. 1,721,416, granted July16, 1929, and assigned to the same assignee as the present application.-

In general, the metallic composition of the Schriiter patents consistsof a carbide of an element of the sixth oup inthe Mendelejefi PeriodicSystem of lements, together with 5 an auxiliary metal of the iron groupin this riodic system. Preferably tungsten caride with about 3 to aboutto of cobalt. is employed. The product contains ordinarily about 6 toabout 15% cobalt with the re- 20 mainder tungsten carbide and is in theform of a sintered product, .the sintering taking place atabout 1375 toabout 1425 (3., depending upon the percent of cobalt in the compositionand the time of sintering. I have discovered an improved method wherebyI can produce a metallic composition of the character set forth suchthat the finished product will be dense and homogeneous and at the sametime very hard.

In carrying out my invention the desired amount of carbon is first firedin 'a hydrogen furnace at about 1500 C; for about four hours. Lampblackis preferably used and the heating m hydrogen is to remove anyimpurities which may be removed by heat. Finely powdered tungsten oxideand the. fired carbon are roughly mixed by hand stirring. .An example ofthe proportions which may be used is: 1280 grams of tungsten oxide to136 grams of carbon. This dry mixture of tungsten oxide and carbon isnow stirred into a solution of cobalt acetate in distilled water. Thereason that-the carbon is first mixed with the tungsten oxide is that byso doing it will be wet by water. When the above" .p'roportions of oxideand carb n areused, 640 grams of cobalt acetate and tfiv employed.

This wet mixture is evaporated to dryness W in the open air and theheating continued 0 liters of water are 1929. Serial No. 382,598.

until the cobalt acetate is broken down to the oxide. The resultingpowder, which is an intimate mixture of tungsten oxide, cobalt oxide,and carbon, is'placed in a graphite crucible and then fired in ahydrogen furnace, at about 1150 C. for about four hours. Thistemperature should beheld quite accurately, the limits being 1125? C.minimum,'to l (lmaximum. v After firing, the mixture is ready forpressin and final sintering. This may be done eit er by carrying out thepressing and sinterin simultaneously. or in separate steps.

at I claim as new and desire to secure by Letters Patent of the UnitedStates, is: o5

1. The process of making a metal composition which comprises introducinga dry mixture of carbon and an oxide of a metal of the sixth oup in theMendelejeif Periodic Sys-- tem o Elements into anlaqueoussolution of acompound of a metal of the iron group in said system which compound iseasily decomposable by heat to the oxide, heating the mixture in air todecompose the compound, firing the mass so obtained in a reducingatmosphere, and pressing and sjntering the fired mass.

2. The process of making a metal composition which comprises introducinga drymixture of carbon and. an oxide of a metal of the sixth oup in theMendelejefi' Periodic System o l llements into anaqueous solution of acompound of a metal of the iron group in said system "which compoundiseasily de-- composable by heat to the oxide, heating the mixture inair to decompose the compound, and firing the mass so' obtained in areducing atmosphere. I i

3. The process 'of making-a metal composition which comprisesintroducing a dry mixture of carbon and tungsten oxide into an aqueoussolution of cobalt acetatei1 heating the mixture in air to decompose t ecobalt acetate, firing the mass so obtained in a reducing. atmosphere,and pressing and 'sintering the fired mass.

4. The process of making-a metal composition which comprises introducinga dry mix ture of carbon and tungsten oxide into an aqueous solution ofcobalt acetate, heating 1Q" the mixture in air to decompose the cobaltacetate, and firing the mass so obtained in a reducing atmosphere.

5. The process of making a dense, hard,

. homogeneous metallic composition WhlOh.

consists in mixing fired carbon with tungsten oxide, introducing thismixture into an aqueous solution of cobalt acetate, drying the mixture,heating the mass until the cobalt w acetate is decomposed to cobaltoxide, firing the resulting mass in a hydrogen atmosphere at about 1150C. for about four hours, then pressing and sintering[.

In Witness whereof, have hereunto set my 15 hand this 30th day of July,1929.

ROY L. ADAMS.

